The latest project I open-sourced on my GitHub account is the Online Book Store shop. of course, it needs a lot more feature but it's just for practice and I will update it later. the UI is designed by myself and the stack is MERN ( Node - Express - React - MongoDB )
it is not a very complex project and beginner and intermediate developers can take a look at the code and have some fun with it.
if I have a proper time later I will add some stuff such as Responsiveness, Unit testing, E2E testing, Author page, etc.
if you would like to participate in the project you can simply send a PR.
Project URL: https://github.com/MRezaSafari/Book-Shop